Electric lamp mounting for reflectors and the like



Aug. 20, 1935. T. w. FRECH ELECTRIC LAMP MOUNTING FOR REFLECTORS AND THE LIKE Filed April 1, 1953 [NI NTER THE'UDURE' WFREEH H s ATTQRNEY Patented Aug. 20, 1935 E LECTRIO LAIHP MOUNTING FOR- RE 7 FLECTORS AND.THE LIKE Theodore W. Frech, Shaker Heights, Ohio, assignor to General Electric Company, a corporation of New York Application April 1, 1933, Serial No. 663,973

My invention relates to mountings for electric lamps in cases where the filament or other light source should bear a definite relation to some associated part or structure, such as a reflector or a lens. The invention is particularly adaptable to vehicle headlamps in which a lamp is'mounted in a reflector such as the well-known paraboloid reflector. The mountings in use at the present time consist of a tubular socket mounted in an opening in the apex of the reflector, the socket having J-shaped slots therein for receiving a pair of radially extending pins mounted on the base of the lamp. The said socket is adjustably mounted in said reflector so that the light source of said lamp may be adjusted to the focal point of the said reflector-which requires a. eomparatively expensive construction, that sometimes fails to hold the filament permanently in the right position.

According to my invention, an adapter is mounted on the base of the lamp so that a portion thereof bears a definite relation to the light source .of said lamp, said adapter comprising a screw thread portion which protrudes through an 5 opening in the apex of the reflector. The lamp is held in said refiector'by means of a nut drawn up on said screw portion of said adapter against the back of the reflector, and provision is preferably made for assuring and maintaining a definite angular relation of the lamp and its filament to the reflector. The pre'focused adapter with the screw and nut holding arrangement provides a simple, accurate, and rigid means of mounting a lamp in a reflector, obviating the use of the conventional form of socket. Further features and advantages of the invention will appear from the following description of a speciesth'ereof and from the drawing.

In the drawing, Fig. 1 is a side view insection of a vehicle headlamp employing my invention; Fig. 2 is a side view of a light source comprising an electric incandescent lamp; Fig. 3 is a rear view of the lamp and adapter; and Fig. 4 .is a side view in section of. a. portion of means of electrical connection to the lamp.

Referring to Figs. 1 and 2, the light source .consists' of an electric incandescent lamp l8 which comprises a bulb ll having a filament l2 therein mounted on leading-in wires l3-|4. The base l5 of said lamp comprises a tubular shell l6 sealed to the bulb II by cement l1. A tubular terminal pin I8 is mounted within said shell iii in insulating material l9, preferably glass. The leading-in wire I3 is connected to the base shell it while the wire I 4 extends through the pin l8 and is soldered thereof.

The filament l2 of the lamp I0 is accurately located with respect to an adapter 28 mounted on to the outer end the base shell IS. The said adapter 20 comprises 5' a flange or collar portion 2| formed at the forward edge of a shoulder portion 22. A reduced neck portion 23, surrounding the base shell I6, is located immediately behind said shoulder 22, the adapter temiinating in'a, threaded sleeve portion 10 24. The adapter 20 is preferably made of sheet metal, with screw threads rolled in the shell or sleeve portion-24, which may be thin enough to give the threads some'resilience The neck por-- tion 23 is of slightly larger diameter than the base l5 IE to permit the lamp to be rocked therein as well as to be shifted axially relative thereto; and thus the rear surface or shoulder afforded by the flange 2| is accurately located with respect to the filament. The adapter 28 can also be so turned on the 20 base l5 that a rearwardly extending key projection or lug on the periphery of the .flange 2| bears a definite angular relation to the filament l2. When the correct relative positions, of filament I 2 and adapter 20 to give the proper posi- 25 tion of the filament in the reflector (as explained hereinafter) have thus been obtained, the said adapter is fixed on the shell IS in this focus adjustmen preferably by solder 26.

The lamp III, with the adapter 20 afiixed there- 30 to, is inserted ima hole 21 in a plane portion 28 at the apex of a reflector 29, the neck portion 22 fitting snugly in said hole. The inside surface of said plane portion 28 is definitely located with respect to the focal point of the reflector, so that when the back surface of the flange. 2| is held thereagainst,. the filament I 2 is located at or near the said focal point-as m'ay'be required to give the light distribution desired. The filament. I2 is also set in a definite angular position by the 40 insertion and engagement of lug 25 in a key seat 80, formed as ,a hole in the portion 28 of the reflector 29. The lamp III is held in place in the, reflector 29 by means of a nut 3| which is screwed onto the threaded portion 24 of the adapter 20, said nut being run up against a washer 32 which may be mounted on the back of the plane portion 28 of the reflector, preferably by solder. Electrical connection is made to the pin I8 '01 the lamp by a helical spring connector 83. Said connector comprises a helical spring 34, one end of which-is clamped on a metal sleeve 35 mounted on the endof the insulating covering 36 of a fiexible stranded conductor 31. The ends of the stranded conductor 31 are bent back over the covering 36 before the metalsleeve 35 is mounted thereon, thus efiecting an' electrical connection from the conductor 3'5, through the sleeve 35, to the spring 34. The spring 34 is deformed so that its internal surface does not lie in a continuous straight line, preferably by offsetting a number of turns 38 (Fig. 4) at the end thereof. Thus when said spring '34 is slipped onto the pin IS, the axis of the spring is brought back to a straight line by elastic flexure of the spring, thus causing the spring to firmly grip the pin. The

spring 34 is covered by an insulating tube 39,

preferably of soft rubber.

The reflector 29 is mounted in a housing 40 by means of a flange 4| at the outer edge thereof, which may be secured to a flange 42 at the front of said housing by screws (not shown). A lens 43 is held over the reflector 29 by a retaining ring 44. The conductor 31 extends through an insulating washer 45, mounted in a hole in the housing 40, to the battery andswitching mechanism.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination of a reflector having a lamp base opening and a key seat; a lamp with its base; a sheet metal adapter shell fixed around said base in focus-adjustment, having a screw thread rolled therein and having its forward end flanged outward to aflord'a shoulder which seats directly in the reflector opening, and having a rearward key projection from the flange; and means screwed on said adapter behind the reflector for holding the adapter shoulder directly against the reflector with its projection engaged in said-seat.

2. An electric lamp for a vehicle headlamp comprising a bulb having a filament sealed therein and a base mounted on said bulb, and an externally screw-threaded cylindrical adapter fixed on said base and having an outward flange thereon adjacentsaid bulb and a key projection extending rearwardly from said flange, said adapter being mounted in focus adjustmentton said base so that the flange thereon is located a predetermined distance from said filament and said key projection is located in a predetermined angular position with respect to said filament.

3. An electric lamp for a vehicle headlamp comprising a bulb having a filament sealed therein and a base mounted on said bulb, and an adapter fixed on said base comprising a cylindrical screw-threaded metal shell having an outward flange formed thereon adjacent said bulb and a key projection extending rearwardly from said flange, said adapter being mounted in focus adjustment on said base so that the flange thereon is located a predetermined distance from said filament and said key projection is located in a predetermined angular position with respect to said filament.

THEODORE W. FRECH. 

